NASA's Chandra X-ray Observatory detected a mysterious flash in a distant region of the sky known as the Chandra Deep Field South.

NASA detected a mysterious burst of bright X-rays in a remote part of the universe and astronomers are trying to figure out its source.

The agency’s Chandra X-ray Observatory discovered the burst in a region of the sky known as the Chandra Deep Field South in October 2014.

"Ever since discovering this source, we've been struggling to understand its origin," Franz Bauer, a researcher at the Pontifical Catholic University of Chile in Santiago, Chile, said in a statement. "It's like we have a jigsaw puzzle, but we don't have all of the pieces."

Bauer is one of the authors of a new study that’s researching the X-ray’s source. The study offers some possible explanations for the burst.